Exemplary embodiments of this invention generally relate to electrical actuation systems and, more particularly, to a lock-out solution for an electrical actuation system of an aircraft.
During installation, service and maintenance of powered equipment, service personnel, such as electricians for example, must assure that the equipment being worked on is isolated from its power source. Although the power source is usually electrical, other power sources such as mechanical, hydraulic, pneumatic, chemical, and thermal may be involved.
When the power source and the equipment are arranged generally at the same location, isolation is not difficult. However, it is common that the power source, e.g. a breaker box, is located relatively far away from the equipment in need of service. Thus, it is possible that after the equipment is isolated at the power source it may be inadvertently powered on by other personnel who do not know that the equipment was intentionally powered off.
“Lock-out” and “Tag-out” refer to safe methods for the complete power isolation of equipment during maintenance or service work. OSHA regulations require the use of locks or tags at control points, such as breaker boxes for example, as warning devices to ensure that personnel are not injured from accidental machine start-ups. While many lock-out and tag-out solutions perform well, none are fool proof. For example, tag-out solutions assume that all personnel can read the same language. Lock-out solutions are often difficult to install and require that the device being locked is pre-equipped with a lock receiving apparatus. In addition, lock-out solutions may be bypassed intentionally or accidentally without the knowledge of the affected personnel.
As aircrafts convert systems previously using hydraulic controls to new electrical solutions, issues arise in preventing unintended start-up of equipment. Many of these systems on an aircraft have large moving surfaces that can create a safety hazard if they were to accidentally move while maintenance personnel are working on them or a neighboring engine. Hydraulic lockout valves were previously used in the hydraulic lines to prevent fluid flow, and therefore movement of these large surfaces. Because these systems are now electrically actuated, an electrical lock out mechanism configured to safely lock out the system by removing power is desired.